Glass fibers are commonly manufactured by supplying molten glass to a bushing, drawing glass fibers from the bushing, and applying a size, typically aqueous based, to the fibers. The fibers are then packaged and dried for further processing.
In order to fabricate composite parts, the glass fibers are often coated in an off-line process with a resin. The resin may be thermosetting or thermoplastic. After resin coating, the impregnated glass fibers may be heated under pressure in a mold to form composite parts.
A variety of methods exist for coating glass fibers with resins which include solution processing, slurry processing, and melt impregnation, which involve passing a finished glass fiber tow through a resin-containing liquid. However, while such methods may be effective, they require one or more off-line processing steps which increase the complexity of production and the cost of the final product, and which may degrade the final product strength due to filament damage during additional handling.
An alternative method has been developed for producing composite strands in an in-line process which involves combining glass fibers with organic fibers to form a composite strand. However, while such a process may be performed in-line, it still has the disadvantage of added cost as the composite strands must be packaged or chopped, shipped and unwound before being further processed and fabricated into parts.
Accordingly, there is still a need in the art for a method and apparatus for producing composite strands and converting the composite strands to final product form in an economical manner without the need for additional packaging, shipping and unwinding steps.